The present invention relates to programmed sewing machines so designed that any of a plurality of preprogrammed patterns can be selected and automatically reproduced.
Programmed sewing machines of the general type in question are already known. Most commonly, these are provided with mechanical memories, usually made of up pattern cams and cooperating cam followers which form any selected one of a plurality of patterns made up of different combinations of stitches. A disadvantage of such mechanical memories is that they are space-consuming, difficult to fit within the limited confines of the sewing machine frame, and tend to increase the weight of the machine.
It has been proposed to replace these mechanical memories with readable memories having the form of perforated tape or magnetic tape. However, if resort is had to control tapes, then a mechanical drive must be provided for advancing the tape and reading off of it the requisite stitch control signals to be applied to the stitch-forming instrumentalities of the machine.
It is also known to make use of an entirely solid-state preprogrammed transistorized pattern control mechanism for sewing machines. However, these known pattern control mechanism are comprised of sizable storages made up of many storage units which must be read out under the control of counters used for addressing purposes. The use of counters for addressing purposes in this context can be disadvantageous in that the storage of stitch control information in the multi-storage-unit storage must be organized in correspondence to the counting sequence followed by the addressing counter. The possibility of freely arranging the stitch control information contained within the plurality of storage units of the storage does not exist.